Child development theory suggests that young children need continuity in caregivers in order to feel secure and form attachments. Indeed, many studies have found that secure attachments serve as developmental antecedents for positive child outcomes. For these reasons, national childcare organizations endorse policies and practices that foster continuity of care and discourage such practices as temporarily moving individual children or teachers into other classrooms to meet ratio requirements. Professional recommendations against temporary classroom transitions are based on theoretical assumptions, as no empirical studies have examined the relationships between temporary transitions and children's outcomes. Our project aims to fill this void by examining (1) the teacher and child characteristics associated with temporary transitions; (2) the relationships between temporary transitions and children's social and cognitive functioning; and (3) the role quality of care plays in mediating those relationships. A unique aspect of this study will be our ability to track changes in quality of care resulting from transitions. When individual children or teachers are moved during the day, their departure from or arrival into a classroom changes the child-teacher ratios, group sizes, and composition of teacher characteristics for all associated classrooms. This necessitates tracking quality at the individual-child level. We used an innovative data collection procedure in which parents filled out sign-in/sign-out sheets at drop-off and pick-up, and staff completed the sheets when they moved classrooms, or when children were moved to another classroom. This will allow us to estimate the percentage of time each child spends with each teacher, and to compute an average child-teacher ratio and group size that is unique to each child. Our ability to capture variation in quality of experience at the individual child-level will allow us to better explore how these differences relate to children's development. The results of this study will provide guidance to practitioners by identifying the conditions under which temporary re-assignments are associated with positive or negative outcomes. We will answer such questions as whether transitions are necessarily associated with poorer social and cognitive functioning, or whether children who move from lower-quality classrooms to higher-quality classrooms can demonstrate positive outcomes, despite receiving care from different teachers. This will help inform sensible approaches to policies regarding classroom transitions. [unreadable] [unreadable] [unreadable]